Chapter Four - Section 1: Introduction

Purpose/Intent

The implementation of a statewide trail system requires
consistency of quality and design throughout Iowa. Trail users from across
the state and throughout the nation should be able to expect a safe, user-friendly,
and accessible trail no matter where in Iowa they travel. In order to encourage
the implementing agencies and organizations to create high-quality trail
facilities, the Iowa Department of Transportation (Iowa DOT) has compiled
a series of design guidelines. These guidelines will be primarily applied
in the implementation of trails in the statewide system and other trails
that receive funding through the Iowa DOT, but they may also be useful as
a design guide for other local trail initiatives.

Trail guidelines are recommendations set forth to help
agencies, local communities, and trail organizations to locate, design, interpret,
and maintain trails. Because they are based on guidelines established by
the American Association of State Highway and Transportation Officials (AASHTO),
the Federal Highway Administration (FHWA), the U.S. Architectural and Transportation
Barriers Compliance Board (U.S. Access Board), and other state agencies
and trail organizations, these guidelines can be considered the best practice
recommendations possible. Deviations from the design guidelines will require
documentation to the Iowa DOT if the project is funded through the Iowa DOT.

The limitation of design guidelines lies in the fact that
any accepted guideline will have exceptions, necessitated by local conditions,
community desire, changing trends, intensity of use, and many other factors.
The strength of design guidelines, however, is that they offer an easy-to-use
summary of extensive design expertise, and they allow for flexibility in
dealing with site-specific issues without the rigid process associated with
design standards. Trail design guidelines should be considered in light of
site-specific issues. Each trail project must consider which design guidelines
are applicable, and under what conditions the trail should deviate from the
guidelines in order to increase user safety or decrease impact to existing
conditions.

When planning trails, agencies should strive to create
environments and experiences that are inclusive of all people. To ensure
that Iowa’s trails meet the needs of all potential users, these design guidelines
address a broad spectrum of ability levels and routinely integrate the needs
of children, older adults, and people with disabilities. In addition to following
these recommendations, designers are encouraged to directly involve trail
users of all abilities and ages within their community early on and throughout
the trail development process.

Goals

The Iowa Trails 2000 design guidelines are established
to help accomplish the following goals:

Recognize various user skillsby recommending different trail
types for different skill levels, especially in the case of bicycle trails.

Minimize impacts to natural resources and private land by setting forth
recommendations for trail location and mitigation strategies.

Ensure the long-term viability of trails by recommending good planning
and design practices.

Users of the Design Guidelines

The Iowa Trails 2000 statewide trails vision will
be planned, designed, and implemented by state agencies, local governments,
and trail groups. The usefulness of these design guidelines, therefore, extends
far beyond the Iowa DOT. The following groups are likely to use the Iowa
Trails 2000 design guidelines:

Policy-makers at various levels will use the design guidelines to plan
for future trail development, especially relating to right-of-way or easement
acquisition and corridor preservation.

Trail planners, both public entities and private consultants, will use
the design guidelines to make recommendations for roadway crossings, possible
corridors, accommodation of various user modes, and other issues.

Trail designers, including private consultants, will use the design
guidelines in the construction documentation process when dealing with trail
alignment, profile, width, cross-section, and surface.

Concept/application reviewers will use the design guidelines to evaluate
the trail for funding. As stated above, deviation from the design guidelines
is possible, but priority may be given to trails that follow the design
goals of the statewide system.

Trail maintenance and operations agencies/ organizations will use the
guidelines in the day-to-day operation of the trail by maintaining appropriate
clear zones, surface condition, and access points.

Resources

Many national and state agencies and plans have set forth
design guidelines. Oftentimes, these guidelines, as in the case of those
written by AASHTO, are the result of extensive testing and evaluation. They
are, therefore, an invaluable resource for trail planners and designers.
The Iowa Trails 2000 design guidelines rely heavily on these resources,
adapting them, where necessary, to specific conditions and policies in the
state of Iowa. Major sources of design guidelines include the following documents.

Guide for the Development of Bicycle Facilities, American Association
of State Highway and Transportation Officials (AASHTO): 1999 (hereafter
referred to as the AASHTO Guide). This is the recognized standard for bicycle
design guidelines. Updated in 1999, this document contains the most current
recommendations available. In addition, trails which will receive federal
transportation funding must adhere to these AASHTO guidelines.

Manual on Uniform Traffic Control Devices

A Policy on Geometric Design of Highways and Streets "Green Book,"
AASHTO. This resource offers design details for Interstate and Primary Road
design.

Iowa Design Manual, Iowa Department of Transportation, Office
of Design. This document offers details and procedures for the design of
transportation facilities in Iowa.

Recommendations for Accessibility Guidelines: Outdoor Developed Areas
Final Report, U.S. Architectural and Transportation Barriers Compliance
Board (U.S. Access Board): 1999. This document is the final report of the
Regulatory Negotiation Committee on Accessibility Guidelines for Outdoor
Developed Areas. This committee developed accessibility recommendations
through a consensus process for a variety of outdoor areas, including trails.
The U.S. Access Board will use the committee’s recommendations, in conjunction
with public comment, to develop standards for compliance with the Americans
with Disabilities Act (ADA). Until standards are developed, this report
contains the best information for meeting the requirements of the ADA.

Designing Sidewalks and Trails for Access: Part II of II: Best Practices
Design Guide, Federal Highway Administration (FHWA): 2000. This document
provides detailed planning and design recommendations for developing pedestrian
and non-motorized multi-use trails that meet the needs of a broad spectrum
of users, including people with disabilities. This document also contains
background information regarding user needs, the benefits of universal design,
and recreation equipment used by people with disabilities.

Selecting Roadway Design Treatments to Accommodate Bicycles,Federal Highway Administration: 1994. This is primarily a planning document
for bicycle facilities, but also offers general design guidelines. This
document makes frequent reference to the AASHTO Guide described above.

Minnesota Bicycle Transportation Planning and Design Guidelines,
Minnesota Department of Transportation: 1996. This document offers both
planning guidance and design guidelines. It is nationally recognized for
its detailed guidelines dealing with roadway crossings.

Oregon Bicycle and Pedestrian Plan,Oregon Department of
Transportation: 1995. This is a detailed, well-organized planning and design
guide. It is known for innovative recommendations for pedestrian and bicycle
accommodation with traffic calming and expressway interchanges.

Portland Pedestrian Design Guide, City of Portland, Oregon, Office
of Transportation: 1998. This guide focuses on the accommodation of pedestrians
in urban areas.

Hennepin County Bicycle Transportation Plan,Hennepin County,
Minnesota, Department of Public Works: 1996. This document gives an extensive
array of guidelines for the implementation of bicycle facilities within
road rights-of-way.